Auto merge of #6583 - pcwalton:serializable-display-list, r=metajack

gfx: Make display lists serializable using `serde`.

This commit introduces the `serde` dependency, which we will use to
serialize messages going between processes in multiprocess Servo.

This also adds a new debugging flag, `-Z print-display-list-json`,
allowing the output of display list serialization to be visualized.
This will be useful for our experiments with alternate rasterizers.

r? @metajack

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30 files changed, 320 insertions, 124 deletions

diff --git a/components/gfx/Cargo.toml b/components/gfx/Cargo.toml
index d051f4baced..b0376d7e335 100644
--- a/components/gfx/Cargo.toml
+++ b/components/gfx/Cargo.toml
@@ -57,6 +57,8 @@ harfbuzz = "0.1"
 smallvec = "0.1"
 string_cache = "0.1"
 euclid = "0.1"
+serde = "*"
+serde_macros = "*"
 
 [target.x86_64-apple-darwin.dependencies]
 core-foundation = "*"
diff --git a/components/gfx/display_list/mod.rs b/components/gfx/display_list/mod.rs
index 442601091df..2aeab109398 100644
--- a/components/gfx/display_list/mod.rs
+++ b/components/gfx/display_list/mod.rs
@@ -25,28 +25,27 @@ use text::TextRun;
 
 use azure::azure::AzFloat;
 use azure::azure_hl::Color;
-
-use std::collections::linked_list::{self, LinkedList};
-use euclid::{Point2D, Rect, SideOffsets2D, Size2D, Matrix2D, Matrix4};
 use euclid::approxeq::ApproxEq;
 use euclid::num::Zero;
+use euclid::{Point2D, Rect, SideOffsets2D, Size2D, Matrix2D, Matrix4};
 use libc::uintptr_t;
-use paint_task::PaintLayer;
 use msg::compositor_msg::{LayerId, LayerKind};
 use net_traits::image::base::Image;
-use util::opts;
-use util::cursor::Cursor;
-use util::linked_list::prepend_from;
-use util::geometry::{self, Au, MAX_RECT, ZERO_RECT};
-use util::mem::HeapSizeOf;
-use util::range::Range;
+use paint_task::PaintLayer;
 use smallvec::SmallVec8;
+use std::collections::linked_list::{self, LinkedList};
 use std::fmt;
 use std::slice::Iter;
 use std::sync::Arc;
 use style::computed_values::{border_style, cursor, filter, image_rendering, mix_blend_mode};
 use style::computed_values::{pointer_events};
 use style::properties::ComputedValues;
+use util::cursor::Cursor;
+use util::geometry::{self, Au, MAX_RECT, ZERO_RECT};
+use util::linked_list::{SerializableLinkedList, prepend_from};
+use util::mem::HeapSizeOf;
+use util::opts;
+use util::range::Range;
 
 // It seems cleaner to have layout code not mention Azure directly, so let's just reexport this for
 // layout to use.
@@ -66,7 +65,7 @@ const MIN_INDENTATION_LENGTH: usize = 4;
 /// Because the script task's GC does not trace layout, node data cannot be safely stored in layout
 /// data structures. Also, layout code tends to be faster when the DOM is not being accessed, for
 /// locality reasons. Using `OpaqueNode` enforces this invariant.
-#[derive(Clone, PartialEq, Copy, Debug, HeapSizeOf)]
+#[derive(Clone, PartialEq, Copy, Debug, HeapSizeOf, Deserialize, Serialize)]
 pub struct OpaqueNode(pub uintptr_t);
 
 impl OpaqueNode {
@@ -82,22 +81,22 @@ impl OpaqueNode {
 ///
 /// TODO(pcwalton): We could reduce the size of this structure with a more "skip list"-like
 /// structure, omitting several pointers and lengths.
-#[derive(HeapSizeOf)]
+#[derive(HeapSizeOf, Deserialize, Serialize)]
 pub struct DisplayList {
     /// The border and backgrounds for the root of this stacking context: steps 1 and 2.
-    pub background_and_borders: LinkedList<DisplayItem>,
+    pub background_and_borders: SerializableLinkedList<DisplayItem>,
     /// Borders and backgrounds for block-level descendants: step 4.
-    pub block_backgrounds_and_borders: LinkedList<DisplayItem>,
+    pub block_backgrounds_and_borders: SerializableLinkedList<DisplayItem>,
     /// Floats: step 5. These are treated as pseudo-stacking contexts.
-    pub floats: LinkedList<DisplayItem>,
+    pub floats: SerializableLinkedList<DisplayItem>,
     /// All non-positioned content.
-    pub content: LinkedList<DisplayItem>,
+    pub content: SerializableLinkedList<DisplayItem>,
     /// All positioned content that does not get a stacking context.
-    pub positioned_content: LinkedList<DisplayItem>,
+    pub positioned_content: SerializableLinkedList<DisplayItem>,
     /// Outlines: step 10.
-    pub outlines: LinkedList<DisplayItem>,
+    pub outlines: SerializableLinkedList<DisplayItem>,
     /// Child stacking contexts.
-    pub children: LinkedList<Arc<StackingContext>>,
+    pub children: SerializableLinkedList<Arc<StackingContext>>,
 }
 
 impl DisplayList {
@@ -105,13 +104,13 @@ impl DisplayList {
     #[inline]
     pub fn new() -> DisplayList {
         DisplayList {
-            background_and_borders: LinkedList::new(),
-            block_backgrounds_and_borders: LinkedList::new(),
-            floats: LinkedList::new(),
-            content: LinkedList::new(),
-            positioned_content: LinkedList::new(),
-            outlines: LinkedList::new(),
-            children: LinkedList::new(),
+            background_and_borders: SerializableLinkedList::new(LinkedList::new()),
+            block_backgrounds_and_borders: SerializableLinkedList::new(LinkedList::new()),
+            floats: SerializableLinkedList::new(LinkedList::new()),
+            content: SerializableLinkedList::new(LinkedList::new()),
+            positioned_content: SerializableLinkedList::new(LinkedList::new()),
+            outlines: SerializableLinkedList::new(LinkedList::new()),
+            children: SerializableLinkedList::new(LinkedList::new()),
         }
     }
 
@@ -119,34 +118,34 @@ impl DisplayList {
     /// `other` in the process.
     #[inline]
     pub fn append_from(&mut self, other: &mut DisplayList) {
-        self.background_and_borders.append(&mut other.background_and_borders);
-        self.block_backgrounds_and_borders.append(&mut other.block_backgrounds_and_borders);
-        self.floats.append(&mut other.floats);
-        self.content.append(&mut other.content);
-        self.positioned_content.append(&mut other.positioned_content);
-        self.outlines.append(&mut other.outlines);
-        self.children.append(&mut other.children);
+        self.background_and_borders.append(&mut *other.background_and_borders);
+        self.block_backgrounds_and_borders.append(&mut *other.block_backgrounds_and_borders);
+        self.floats.append(&mut *other.floats);
+        self.content.append(&mut *other.content);
+        self.positioned_content.append(&mut *other.positioned_content);
+        self.outlines.append(&mut *other.outlines);
+        self.children.append(&mut *other.children);
     }
 
     /// Merges all display items from all non-float stacking levels to the `float` stacking level.
     #[inline]
     pub fn form_float_pseudo_stacking_context(&mut self) {
-        prepend_from(&mut self.floats, &mut self.outlines);
-        prepend_from(&mut self.floats, &mut self.positioned_content);
-        prepend_from(&mut self.floats, &mut self.content);
-        prepend_from(&mut self.floats, &mut self.block_backgrounds_and_borders);
-        prepend_from(&mut self.floats, &mut self.background_and_borders);
+        prepend_from(&mut *self.floats, &mut *self.outlines);
+        prepend_from(&mut *self.floats, &mut *self.positioned_content);
+        prepend_from(&mut *self.floats, &mut *self.content);
+        prepend_from(&mut *self.floats, &mut *self.block_backgrounds_and_borders);
+        prepend_from(&mut *self.floats, &mut *self.background_and_borders);
     }
 
     /// Merges all display items from all non-positioned-content stacking levels to the
     /// positioned-content stacking level.
     #[inline]
     pub fn form_pseudo_stacking_context_for_positioned_content(&mut self) {
-        prepend_from(&mut self.positioned_content, &mut self.outlines);
-        prepend_from(&mut self.positioned_content, &mut self.content);
-        prepend_from(&mut self.positioned_content, &mut self.floats);
-        prepend_from(&mut self.positioned_content, &mut self.block_backgrounds_and_borders);
-        prepend_from(&mut self.positioned_content, &mut self.background_and_borders);
+        prepend_from(&mut *self.positioned_content, &mut *self.outlines);
+        prepend_from(&mut *self.positioned_content, &mut *self.content);
+        prepend_from(&mut *self.positioned_content, &mut *self.floats);
+        prepend_from(&mut *self.positioned_content, &mut *self.block_backgrounds_and_borders);
+        prepend_from(&mut *self.positioned_content, &mut *self.background_and_borders);
     }
 
     /// Returns a list of all items in this display list concatenated together. This is extremely
@@ -219,7 +218,7 @@ impl DisplayList {
     }
 }
 
-#[derive(HeapSizeOf)]
+#[derive(HeapSizeOf, Deserialize, Serialize)]
 /// Represents one CSS stacking context, which may or may not have a hardware layer.
 pub struct StackingContext {
     /// The display items that make up this stacking context.
@@ -443,7 +442,8 @@ impl StackingContext {
 
         } else {
             // Optimize the display list to throw out out-of-bounds display items and so forth.
-            let display_list = DisplayListOptimizer::new(tile_bounds).optimize(&*self.display_list);
+            let display_list =
+                DisplayListOptimizer::new(tile_bounds).optimize(&*self.display_list);
 
             self.draw_into_context(&display_list,
                                    paint_context,
@@ -515,12 +515,16 @@ impl StackingContext {
                         // If the point is inside the border, it didn't hit the border!
                         let interior_rect =
                             Rect::new(
-                                Point2D::new(border.base.bounds.origin.x + border.border_widths.left,
-                                             border.base.bounds.origin.y + border.border_widths.top),
+                                Point2D::new(border.base.bounds.origin.x +
+                                             border.border_widths.left,
+                                             border.base.bounds.origin.y +
+                                             border.border_widths.top),
                                 Size2D::new(border.base.bounds.size.width -
-                                                (border.border_widths.left + border.border_widths.right),
+                                                (border.border_widths.left +
+                                                 border.border_widths.right),
                                             border.base.bounds.size.height -
-                                                (border.border_widths.top + border.border_widths.bottom)));
+                                                (border.border_widths.top +
+                                                 border.border_widths.bottom)));
                         if geometry::rect_contains_point(interior_rect, point) {
                             continue
                         }
@@ -541,7 +545,7 @@ impl StackingContext {
 
         debug_assert!(!topmost_only || result.is_empty());
         let frac_point = self.transform.transform_point(&Point2D::new(point.x.to_f32_px(),
-                                                                 point.y.to_f32_px()));
+                                                                      point.y.to_f32_px()));
         point = Point2D::new(Au::from_f32_px(frac_point.x), Au::from_f32_px(frac_point.y));
 
         // Iterate through display items in reverse stacking order. Steps here refer to the
@@ -639,7 +643,7 @@ pub fn find_stacking_context_with_layer_id(this: &Arc<StackingContext>, layer_id
 }
 
 /// One drawing command in the list.
-#[derive(Clone, HeapSizeOf)]
+#[derive(Clone, Deserialize, HeapSizeOf, Serialize)]
 pub enum DisplayItem {
     SolidColorClass(Box<SolidColorDisplayItem>),
     TextClass(Box<TextDisplayItem>),
@@ -651,7 +655,7 @@ pub enum DisplayItem {
 }
 
 /// Information common to all display items.
-#[derive(Clone, HeapSizeOf)]
+#[derive(Clone, Deserialize, HeapSizeOf, Serialize)]
 pub struct BaseDisplayItem {
     /// The boundaries of the display item, in layer coordinates.
     pub bounds: Rect<Au>,
@@ -679,7 +683,7 @@ impl BaseDisplayItem {
 /// A clipping region for a display item. Currently, this can describe rectangles, rounded
 /// rectangles (for `border-radius`), or arbitrary intersections of the two. Arbitrary transforms
 /// are not supported because those are handled by the higher-level `StackingContext` abstraction.
-#[derive(Clone, PartialEq, Debug, HeapSizeOf)]
+#[derive(Clone, PartialEq, Debug, HeapSizeOf, Deserialize, Serialize)]
 pub struct ClippingRegion {
     /// The main rectangular region. This does not include any corners.
     pub main: Rect<Au>,
@@ -693,7 +697,7 @@ pub struct ClippingRegion {
 /// A complex clipping region. These don't as easily admit arbitrary intersection operations, so
 /// they're stored in a list over to the side. Currently a complex clipping region is just a
 /// rounded rectangle, but the CSS WGs will probably make us throw more stuff in here eventually.
-#[derive(Clone, PartialEq, Debug, HeapSizeOf)]
+#[derive(Clone, PartialEq, Debug, HeapSizeOf, Deserialize, Serialize)]
 pub struct ComplexClippingRegion {
     /// The boundaries of the rectangle.
     pub rect: Rect<Au>,
@@ -805,7 +809,7 @@ impl ClippingRegion {
 /// Metadata attached to each display item. This is useful for performing auxiliary tasks with
 /// the display list involving hit testing: finding the originating DOM node and determining the
 /// cursor to use when the element is hovered over.
-#[derive(Clone, Copy, HeapSizeOf)]
+#[derive(Clone, Copy, HeapSizeOf, Deserialize, Serialize)]
 pub struct DisplayItemMetadata {
     /// The DOM node from which this display item originated.
     pub node: OpaqueNode,
@@ -834,7 +838,7 @@ impl DisplayItemMetadata {
 }
 
 /// Paints a solid color.
-#[derive(Clone, HeapSizeOf)]
+#[derive(Clone, HeapSizeOf, Deserialize, Serialize)]
 pub struct SolidColorDisplayItem {
     /// Fields common to all display items.
     pub base: BaseDisplayItem,
@@ -844,7 +848,7 @@ pub struct SolidColorDisplayItem {
 }
 
 /// Paints text.
-#[derive(Clone, HeapSizeOf)]
+#[derive(Clone, HeapSizeOf, Deserialize, Serialize)]
 pub struct TextDisplayItem {
     /// Fields common to all display items.
     pub base: BaseDisplayItem,
@@ -869,7 +873,7 @@ pub struct TextDisplayItem {
     pub blur_radius: Au,
 }
 
-#[derive(Clone, Eq, PartialEq, HeapSizeOf)]
+#[derive(Clone, Eq, PartialEq, HeapSizeOf, Deserialize, Serialize)]
 pub enum TextOrientation {
     Upright,
     SidewaysLeft,
@@ -877,7 +881,7 @@ pub enum TextOrientation {
 }
 
 /// Paints an image.
-#[derive(Clone, HeapSizeOf)]
+#[derive(Clone, HeapSizeOf, Deserialize, Serialize)]
 pub struct ImageDisplayItem {
     pub base: BaseDisplayItem,
     #[ignore_heap_size_of = "Because it is non-owning"]
@@ -895,7 +899,7 @@ pub struct ImageDisplayItem {
 
 
 /// Paints a gradient.
-#[derive(Clone)]
+#[derive(Clone, Deserialize, Serialize)]
 pub struct GradientDisplayItem {
     /// Fields common to all display items.
     pub base: BaseDisplayItem,
@@ -926,7 +930,7 @@ impl HeapSizeOf for GradientDisplayItem {
 
 
 /// Paints a border.
-#[derive(Clone, HeapSizeOf)]
+#[derive(Clone, HeapSizeOf, Deserialize, Serialize)]
 pub struct BorderDisplayItem {
     /// Fields common to all display items.
     pub base: BaseDisplayItem,
@@ -949,7 +953,7 @@ pub struct BorderDisplayItem {
 /// Information about the border radii.
 ///
 /// TODO(pcwalton): Elliptical radii.
-#[derive(Clone, Default, PartialEq, Debug, Copy, HeapSizeOf)]
+#[derive(Clone, Default, PartialEq, Debug, Copy, HeapSizeOf, Deserialize, Serialize)]
 pub struct BorderRadii<T> {
     pub top_left: T,
     pub top_right: T,
@@ -979,7 +983,7 @@ impl<T> BorderRadii<T> where T: PartialEq + Zero + Clone {
 }
 
 /// Paints a line segment.
-#[derive(Clone, HeapSizeOf)]
+#[derive(Clone, HeapSizeOf, Deserialize, Serialize)]
 pub struct LineDisplayItem {
     pub base: BaseDisplayItem,
 
@@ -991,7 +995,7 @@ pub struct LineDisplayItem {
 }
 
 /// Paints a box shadow per CSS-BACKGROUNDS.
-#[derive(Clone, HeapSizeOf)]
+#[derive(Clone, HeapSizeOf, Deserialize, Serialize)]
 pub struct BoxShadowDisplayItem {
     /// Fields common to all display items.
     pub base: BaseDisplayItem,
@@ -1016,7 +1020,7 @@ pub struct BoxShadowDisplayItem {
 }
 
 /// How a box shadow should be clipped.
-#[derive(Clone, Copy, Debug, PartialEq, HeapSizeOf)]
+#[derive(Clone, Copy, Debug, PartialEq, HeapSizeOf, Deserialize, Serialize)]
 pub enum BoxShadowClipMode {
     /// No special clipping should occur. This is used for (shadowed) text decorations.
     None,
diff --git a/components/gfx/display_list/optimizer.rs b/components/gfx/display_list/optimizer.rs
index d7a5297dd1f..e6788d3642c 100644
--- a/components/gfx/display_list/optimizer.rs
+++ b/components/gfx/display_list/optimizer.rs
@@ -37,7 +37,8 @@ impl DisplayListOptimizer {
         self.add_in_bounds_display_items(&mut result.content, display_list.content.iter());
         self.add_in_bounds_display_items(&mut result.positioned_content,
                                          display_list.positioned_content.iter());
-        self.add_in_bounds_display_items(&mut result.outlines, display_list.outlines.iter());
+        self.add_in_bounds_display_items(&mut result.outlines,
+                                         display_list.outlines.iter());
         self.add_in_bounds_stacking_contexts(&mut result.children, display_list.children.iter());
         result
     }
diff --git a/components/gfx/font.rs b/components/gfx/font.rs
index 27f872ba11f..f263cc8c607 100644
--- a/components/gfx/font.rs
+++ b/components/gfx/font.rs
@@ -69,7 +69,7 @@ pub trait FontTableMethods {
     fn with_buffer<F>(&self, F) where F: FnOnce(*const u8, usize);
 }
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, Deserialize, Serialize)]
 pub struct FontMetrics {
     pub underline_size:   Au,
     pub underline_offset: Au,
diff --git a/components/gfx/lib.rs b/components/gfx/lib.rs
index 5f147f8adb4..c711ae1fc9a 100644
--- a/components/gfx/lib.rs
+++ b/components/gfx/lib.rs
@@ -14,9 +14,11 @@
 #![feature(vec_push_all)]
 
 #![plugin(plugins)]
+#![plugin(serde_macros)]
 
 #[macro_use]
 extern crate log;
+extern crate serde;
 
 extern crate azure;
 #[macro_use] extern crate bitflags;
diff --git a/components/gfx/paint_task.rs b/components/gfx/paint_task.rs
index 928028a5dc6..308b270326c 100644
--- a/components/gfx/paint_task.rs
+++ b/components/gfx/paint_task.rs
@@ -40,7 +40,7 @@ use util::task_state;
 use util::task::spawn_named;
 
 /// Information about a hardware graphics layer that layout sends to the painting task.
-#[derive(Clone)]
+#[derive(Clone, Deserialize, Serialize)]
 pub struct PaintLayer {
     /// A per-pipeline ID describing this layer that should be stable across reflows.
     pub id: LayerId,
@@ -353,18 +353,23 @@ impl<C> PaintTask<C> where C: PaintListener + Send + 'static {
             let transform = transform.mul(&stacking_context.transform);
             let perspective = perspective.mul(&stacking_context.perspective);
 
-            let (next_parent_id, page_position, transform, perspective) = match stacking_context.layer {
+            let (next_parent_id, page_position, transform, perspective) =
+                match stacking_context.layer {
                 Some(ref paint_layer) => {
-                    // Layers start at the top left of their overflow rect, as far as the info we give to
-                    // the compositor is concerned.
+                    // Layers start at the top left of their overflow rect, as far as the info we
+                    // give to the compositor is concerned.
                     let overflow_relative_page_position = *page_position +
                                                           stacking_context.bounds.origin +
                                                           stacking_context.overflow.origin;
                     let layer_position =
-                        Rect::new(Point2D::new(overflow_relative_page_position.x.to_nearest_px() as f32,
-                                               overflow_relative_page_position.y.to_nearest_px() as f32),
-                                  Size2D::new(stacking_context.overflow.size.width.to_nearest_px() as f32,
-                                              stacking_context.overflow.size.height.to_nearest_px() as f32));
+                        Rect::new(Point2D::new(overflow_relative_page_position.x.to_nearest_px() as
+                                               f32,
+                                               overflow_relative_page_position.y.to_nearest_px() as
+                                               f32),
+                                  Size2D::new(stacking_context.overflow.size.width.to_nearest_px()
+                                              as f32,
+                                              stacking_context.overflow.size.height.to_nearest_px()
+                                              as f32));
 
                     let establishes_3d_context = stacking_context.establishes_3d_context;
 
@@ -395,12 +400,7 @@ impl<C> PaintTask<C> where C: PaintListener + Send + 'static {
             };
 
             for kid in stacking_context.display_list.children.iter() {
-                build(properties,
-                      &**kid,
-                      &page_position,
-                      &transform,
-                      &perspective,
-                      next_parent_id);
+                build(properties, &**kid, &page_position, &transform, &perspective, next_parent_id)
             }
         }
     }
diff --git a/components/gfx/platform/freetype/font_template.rs b/components/gfx/platform/freetype/font_template.rs
index bdd12616e86..305c643ea95 100644
--- a/components/gfx/platform/freetype/font_template.rs
+++ b/components/gfx/platform/freetype/font_template.rs
@@ -10,6 +10,7 @@ use string_cache::Atom;
 /// The identifier is an absolute path, and the bytes
 /// field is the loaded data that can be passed to
 /// freetype and azure directly.
+#[derive(Deserialize, Serialize)]
 pub struct FontTemplateData {
     pub bytes: Vec<u8>,
     pub identifier: Atom,
diff --git a/components/gfx/platform/macos/font.rs b/components/gfx/platform/macos/font.rs
index 23c14b3fd61..a6e431407e1 100644
--- a/components/gfx/platform/macos/font.rs
+++ b/components/gfx/platform/macos/font.rs
@@ -64,7 +64,7 @@ impl FontHandleMethods for FontHandle {
             Some(s) => s.to_f64_px(),
             None => 0.0
         };
-        match template.ctfont {
+        match *template.ctfont {
             Some(ref ctfont) => {
                 Ok(FontHandle {
                     font_data: template.clone(),
diff --git a/components/gfx/platform/macos/font_template.rs b/components/gfx/platform/macos/font_template.rs
index efaabe08a13..e5c0c9c194b 100644
--- a/components/gfx/platform/macos/font_template.rs
+++ b/components/gfx/platform/macos/font_template.rs
@@ -7,14 +7,27 @@ use core_graphics::font::CGFont;
 use core_text::font::CTFont;
 use core_text;
 
+use serde::de::{Error, Visitor};
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
+use std::borrow::ToOwned;
+use std::ops::Deref;
 use string_cache::Atom;
 
 /// Platform specific font representation for mac.
 /// The identifier is a PostScript font name. The
 /// CTFont object is cached here for use by the
 /// paint functions that create CGFont references.
+#[derive(Deserialize, Serialize)]
 pub struct FontTemplateData {
-    pub ctfont: Option<CTFont>,
+    /// The `CTFont` object, if present. This is cached here so that we don't have to keep creating
+    /// `CTFont` instances over and over. It can always be recreated from the `identifier` and/or
+    /// `font_data` fields.
+    ///
+    /// When sending a `FontTemplateData` instance across processes, this will be set to `None` on
+    /// the other side, because `CTFont` instances cannot be sent across processes. This is
+    /// harmless, however, because it can always be recreated.
+    pub ctfont: CachedCTFont,
+
     pub identifier: Atom,
     pub font_data: Option<Vec<u8>>
 }
@@ -39,9 +52,43 @@ impl FontTemplateData {
         };
 
         FontTemplateData {
-            ctfont: ctfont,
+            ctfont: CachedCTFont(ctfont),
             identifier: identifier.to_owned(),
             font_data: font_data
         }
     }
 }
+
+pub struct CachedCTFont(Option<CTFont>);
+
+impl Deref for CachedCTFont {
+    type Target = Option<CTFont>;
+    fn deref(&self) -> &Option<CTFont> {
+        &self.0
+    }
+}
+
+impl Serialize for CachedCTFont {
+    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error> where S: Serializer {
+        serializer.visit_none()
+    }
+}
+
+impl Deserialize for CachedCTFont {
+    fn deserialize<D>(deserializer: &mut D) -> Result<CachedCTFont, D::Error>
+                      where D: Deserializer {
+        struct NoneOptionVisitor;
+
+        impl Visitor for NoneOptionVisitor {
+            type Value = CachedCTFont;
+
+            #[inline]
+            fn visit_none<E>(&mut self) -> Result<CachedCTFont,E> where E: Error {
+                Ok(CachedCTFont(None))
+            }
+        }
+
+        deserializer.visit_option(NoneOptionVisitor)
+    }
+}
+
diff --git a/components/gfx/text/glyph.rs b/components/gfx/text/glyph.rs
index d1dc0b8297e..435096486a8 100644
--- a/components/gfx/text/glyph.rs
+++ b/components/gfx/text/glyph.rs
@@ -19,7 +19,7 @@ use util::vec::*;
 /// In the uncommon case (multiple glyphs per unicode character, large glyph index/advance, or
 /// glyph offsets), we pack the glyph count into GlyphEntry, and store the other glyph information
 /// in DetailedGlyphStore.
-#[derive(Clone, Debug, Copy)]
+#[derive(Clone, Debug, Copy, Deserialize, Serialize)]
 struct GlyphEntry {
     value: u32,
 }
@@ -250,7 +250,7 @@ impl GlyphEntry {
 
 // Stores data for a detailed glyph, in the case that several glyphs
 // correspond to one character, or the glyph's data couldn't be packed.
-#[derive(Clone, Debug, Copy)]
+#[derive(Clone, Debug, Copy, Deserialize, Serialize)]
 struct DetailedGlyph {
     id: GlyphId,
     // glyph's advance, in the text's direction (LTR or RTL)
@@ -269,7 +269,7 @@ impl DetailedGlyph {
     }
 }
 
-#[derive(PartialEq, Clone, Eq, Debug, Copy)]
+#[derive(PartialEq, Clone, Eq, Debug, Copy, Deserialize, Serialize)]
 struct DetailedGlyphRecord {
     // source string offset/GlyphEntry offset in the TextRun
     entry_offset: CharIndex,
@@ -293,7 +293,7 @@ impl Ord for DetailedGlyphRecord {
 // until a lookup is actually performed; this matches the expected
 // usage pattern of setting/appending all the detailed glyphs, and
 // then querying without setting.
-#[derive(Clone)]
+#[derive(Clone, Deserialize, Serialize)]
 struct DetailedGlyphStore {
     // TODO(pcwalton): Allocation of this buffer is expensive. Consider a small-vector
     // optimization.
@@ -500,7 +500,7 @@ impl<'a> GlyphInfo<'a> {
 /// |               +---+---+                     |
 /// +---------------------------------------------+
 /// ~~~
-#[derive(Clone)]
+#[derive(Clone, Deserialize, Serialize)]
 pub struct GlyphStore {
     // TODO(pcwalton): Allocation of this buffer is expensive. Consider a small-vector
     // optimization.
@@ -515,7 +515,7 @@ pub struct GlyphStore {
 }
 
 int_range_index! {
-    #[derive(RustcEncodable)]
+    #[derive(Deserialize, Serialize, RustcEncodable)]
     #[doc = "An index that refers to a character in a text run. This could \
              point to the middle of a glyph."]
     #[derive(HeapSizeOf)]
diff --git a/components/gfx/text/text_run.rs b/components/gfx/text/text_run.rs
index a9bf0b409f5..4389cbc5a1c 100644
--- a/components/gfx/text/text_run.rs
+++ b/components/gfx/text/text_run.rs
@@ -14,7 +14,7 @@ use std::sync::Arc;
 use text::glyph::{CharIndex, GlyphStore};
 
 /// A single "paragraph" of text in one font size and style.
-#[derive(Clone)]
+#[derive(Clone, Deserialize, Serialize)]
 pub struct TextRun {
     /// The UTF-8 string represented by this text run.
     pub text: Arc<String>,
@@ -26,7 +26,7 @@ pub struct TextRun {
 }
 
 /// A single series of glyphs within a text run.
-#[derive(Clone)]
+#[derive(Clone, Deserialize, Serialize)]
 pub struct GlyphRun {
     /// The glyphs.
     pub glyph_store: Arc<GlyphStore>,
diff --git a/components/layout/Cargo.toml b/components/layout/Cargo.toml
index dfb2e12cb93..5feddfb72eb 100644
--- a/components/layout/Cargo.toml
+++ b/components/layout/Cargo.toml
@@ -71,3 +71,6 @@ smallvec = "0.1"
 string_cache = "0.1"
 string_cache_plugin = "0.1"
 euclid = "0.1"
+serde = "*"
+serde_macros = "*"
+
diff --git a/components/layout/display_list_builder.rs b/components/layout/display_list_builder.rs
index e9ba8dff3d2..b3ad6742f4d 100644
--- a/components/layout/display_list_builder.rs
+++ b/components/layout/display_list_builder.rs
@@ -829,7 +829,9 @@ impl FragmentDisplayListBuilding for Fragment {
 
         let line_display_item = box LineDisplayItem {
             base: BaseDisplayItem::new(baseline,
-                                       DisplayItemMetadata::new(self.node, style, Cursor::DefaultCursor),
+                                       DisplayItemMetadata::new(self.node,
+                                                                style,
+                                                                Cursor::DefaultCursor),
                                        (*clip).clone()),
             color: color::rgb(0, 200, 0),
             style: border_style::T::dashed,
diff --git a/components/layout/layout_task.rs b/components/layout/layout_task.rs
index e5141726865..860762aecca 100644
--- a/components/layout/layout_task.rs
+++ b/components/layout/layout_task.rs
@@ -58,6 +58,7 @@ use script::layout_interface::{NewLayoutTaskInfo, Msg, Reflow, ReflowGoal, Reflo
 use script::layout_interface::{ScriptLayoutChan, ScriptReflow, TrustedNodeAddress};
 use script_traits::{ConstellationControlMsg, LayoutControlMsg, OpaqueScriptLayoutChannel};
 use script_traits::{ScriptControlChan, StylesheetLoadResponder};
+use serde::json;
 use std::borrow::ToOwned;
 use std::cell::Cell;
 use std::collections::HashMap;
@@ -907,6 +908,9 @@ impl LayoutTask {
                     println!("#### start printing display list.");
                     stacking_context.print("#".to_owned());
                 }
+                if opts::get().dump_display_list_json {
+                    println!("{}", json::to_string_pretty(&stacking_context).unwrap());
+                }
 
                 rw_data.stacking_context = Some(stacking_context.clone());
 
diff --git a/components/layout/lib.rs b/components/layout/lib.rs
index 618a16e9628..f16272f0d22 100644
--- a/components/layout/lib.rs
+++ b/components/layout/lib.rs
@@ -5,6 +5,7 @@
 #![feature(append)]
 #![feature(arc_unique)]
 #![feature(box_syntax)]
+#![feature(custom_derive)]
 #![feature(filling_drop)]
 #![feature(hashmap_hasher)]
 #![feature(heap_api)]
@@ -36,7 +37,6 @@ extern crate profile_traits;
 #[macro_use]
 extern crate util;
 
-extern crate rustc_serialize;
 extern crate azure;
 extern crate canvas_traits;
 extern crate clock_ticks;
@@ -50,9 +50,11 @@ extern crate ipc_channel;
 extern crate layout_traits;
 extern crate libc;
 extern crate msg;
+extern crate rustc_serialize;
 extern crate script;
 extern crate script_traits;
 extern crate selectors;
+extern crate serde;
 extern crate smallvec;
 extern crate string_cache;
 extern crate style;
diff --git a/components/msg/compositor_msg.rs b/components/msg/compositor_msg.rs
index df05548b6a5..3a1d098eb36 100644
--- a/components/msg/compositor_msg.rs
+++ b/components/msg/compositor_msg.rs
@@ -60,7 +60,7 @@ pub enum LayerKind {
 }
 
 /// The scrolling policy of a layer.
-#[derive(Clone, PartialEq, Eq, Copy)]
+#[derive(Clone, PartialEq, Eq, Copy, Deserialize, Serialize)]
 pub enum ScrollPolicy {
     /// These layers scroll when the parent receives a scrolling message.
     Scrollable,
diff --git a/components/net_traits/Cargo.toml b/components/net_traits/Cargo.toml
index ca6a1515658..0cf033bd1bd 100644
--- a/components/net_traits/Cargo.toml
+++ b/components/net_traits/Cargo.toml
@@ -24,4 +24,6 @@ log = "*"
 url = "0.2.35"
 hyper = "0.6"
 euclid = "0.1"
+serde = "*"
+serde_macros = "*"
 
diff --git a/components/net_traits/image/base.rs b/components/net_traits/image/base.rs
index c81158e416e..1a9ee30cfb5 100644
--- a/components/net_traits/image/base.rs
+++ b/components/net_traits/image/base.rs
@@ -10,6 +10,7 @@ use util::vec::byte_swap;
 // FIXME: Images must not be copied every frame. Instead we should atomically
 // reference count them.
 
+#[derive(Deserialize, Serialize)]
 pub enum PixelFormat {
     K8,         // Luminance channel only
     KA8,        // Luminance + alpha
@@ -17,6 +18,7 @@ pub enum PixelFormat {
     RGBA8,      // RGB + alpha, 8 bits per channel
 }
 
+#[derive(Deserialize, Serialize)]
 pub struct Image {
     pub width: u32,
     pub height: u32,
diff --git a/components/net_traits/lib.rs b/components/net_traits/lib.rs
index 6753b372ba8..620d6c39aaf 100644
--- a/components/net_traits/lib.rs
+++ b/components/net_traits/lib.rs
@@ -3,15 +3,19 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #![feature(box_syntax)]
+#![feature(custom_derive)]
+#![feature(plugin)]
 #![feature(slice_patterns)]
 #![feature(step_by)]
 #![feature(vec_push_all)]
+#![plugin(serde_macros)]
 
 extern crate euclid;
 extern crate hyper;
 #[macro_use]
 extern crate log;
 extern crate png;
+extern crate serde;
 extern crate stb_image;
 extern crate url;
 extern crate util;
diff --git a/components/servo/Cargo.lock b/components/servo/Cargo.lock
index a78c72a3c02..7f7d7a4226b 100644
--- a/components/servo/Cargo.lock
+++ b/components/servo/Cargo.lock
@@ -445,9 +445,11 @@ dependencies = [
  "rand 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "script_traits 0.0.1",
+ "serde 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_macros 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "skia 0.0.20130412 (git+https://github.com/servo/skia)",
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "time 0.1.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 0.2.35 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -579,7 +581,7 @@ dependencies = [
  "mac 0.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "phf 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "phf_macros 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_plugin 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "tendril 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "time 0.1.26 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -720,8 +722,10 @@ dependencies = [
  "script 0.0.1",
  "script_traits 0.0.1",
  "selectors 0.1.0 (git+https://github.com/servo/rust-selectors)",
+ "serde 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_macros 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_plugin 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "url 0.2.35 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -883,6 +887,8 @@ dependencies = [
  "log 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "msg 0.0.1",
  "png 0.1.0 (git+https://github.com/servo/rust-png)",
+ "serde 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_macros 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "stb_image 0.1.0 (git+https://github.com/servo/rust-stb-image)",
  "url 0.2.35 (registry+https://github.com/rust-lang/crates.io-index)",
  "util 0.0.1",
@@ -1142,7 +1148,7 @@ dependencies = [
  "script_traits 0.0.1",
  "selectors 0.1.0 (git+https://github.com/servo/rust-selectors)",
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_plugin 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "tendril 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1189,7 +1195,7 @@ dependencies = [
  "matches 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "quicksort 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_plugin 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1269,13 +1275,14 @@ dependencies = [
 
 [[package]]
 name = "string_cache"
-version = "0.1.5"
+version = "0.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "lazy_static 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "phf 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "phf_macros 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_plugin 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_shared 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -1311,8 +1318,10 @@ dependencies = [
  "plugins 0.0.1",
  "rustc-serialize 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "selectors 0.1.0 (git+https://github.com/servo/rust-selectors)",
+ "serde 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_macros 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_plugin 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 0.2.35 (registry+https://github.com/rust-lang/crates.io-index)",
  "util 0.0.1",
@@ -1325,7 +1334,7 @@ dependencies = [
  "cssparser 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "selectors 0.1.0 (git+https://github.com/servo/rust-selectors)",
- "string_cache 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_plugin 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "url 0.2.35 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/components/style/Cargo.toml b/components/style/Cargo.toml
index 10f0e40f658..3fe248a56c0 100644
--- a/components/style/Cargo.toml
+++ b/components/style/Cargo.toml
@@ -34,3 +34,6 @@ smallvec = "0.1"
 string_cache = "0.1"
 string_cache_plugin = "0.1"
 euclid = "0.1"
+serde = "*"
+serde_macros = "*"
+
diff --git a/components/style/lib.rs b/components/style/lib.rs
index bd84d33884a..d4d928642da 100644
--- a/components/style/lib.rs
+++ b/components/style/lib.rs
@@ -10,9 +10,9 @@
 #![feature(hasher_write)]
 #![feature(plugin)]
 #![feature(vec_push_all)]
-#![feature(vec_push_all)]
 
 #![plugin(string_cache_plugin)]
+#![plugin(serde_macros)]
 #![plugin(plugins)]
 
 #[macro_use] extern crate log;
@@ -20,6 +20,7 @@
 
 extern crate fnv;
 extern crate euclid;
+extern crate serde;
 extern crate smallvec;
 extern crate url;
 
diff --git a/components/style/properties.mako.rs b/components/style/properties.mako.rs
index 29bccc4c28b..ca3dfb5bbaf 100644
--- a/components/style/properties.mako.rs
+++ b/components/style/properties.mako.rs
@@ -3050,7 +3050,7 @@ pub mod longhands {
             use values::CSSFloat;
             use values::specified::{Angle};
 
-            #[derive(Clone, PartialEq, Debug, HeapSizeOf)]
+            #[derive(Clone, PartialEq, Debug, HeapSizeOf, Deserialize, Serialize)]
             pub enum Filter {
                 Blur(Au),
                 Brightness(CSSFloat),
@@ -3063,7 +3063,7 @@ pub mod longhands {
                 Sepia(CSSFloat),
             }
 
-            #[derive(Clone, PartialEq, Debug, HeapSizeOf)]
+            #[derive(Clone, PartialEq, Debug, HeapSizeOf, Deserialize, Serialize)]
             pub struct T { pub filters: Vec<Filter> }
 
             impl T {
@@ -3857,7 +3857,7 @@ pub mod longhands {
             use cssparser::ToCss;
             use std::fmt;
 
-            #[derive(Copy, Clone, Debug, PartialEq, HeapSizeOf)]
+            #[derive(Copy, Clone, Debug, PartialEq, HeapSizeOf, Deserialize, Serialize)]
             pub enum T {
                 Auto,
                 CrispEdges,
diff --git a/components/style/values.rs b/components/style/values.rs
index 3fad8588a18..3411db28fe5 100644
--- a/components/style/values.rs
+++ b/components/style/values.rs
@@ -13,6 +13,7 @@ macro_rules! define_css_keyword_enum {
     ($name: ident: $( $css: expr => $variant: ident ),+) => {
         #[allow(non_camel_case_types)]
         #[derive(Clone, Eq, PartialEq, Copy, Hash, RustcEncodable, Debug, HeapSizeOf)]
+        #[derive(Deserialize, Serialize)]
         pub enum $name {
             $( $variant ),+
         }
@@ -44,6 +45,7 @@ macro_rules! define_numbered_css_keyword_enum {
     ($name: ident: $( $css: expr => $variant: ident = $value: expr ),+) => {
         #[allow(non_camel_case_types)]
         #[derive(Clone, Eq, PartialEq, PartialOrd, Ord, Copy, RustcEncodable, Debug, HeapSizeOf)]
+        #[derive(Deserialize, Serialize)]
         pub enum $name {
             $( $variant = $value ),+
         }
@@ -645,7 +647,7 @@ pub mod specified {
         }
     }
 
-    #[derive(Clone, PartialEq, PartialOrd, Copy, Debug, HeapSizeOf)]
+    #[derive(Clone, PartialEq, PartialOrd, Copy, Debug, HeapSizeOf, Deserialize, Serialize)]
     pub struct Angle(pub CSSFloat);
 
     impl ToCss for Angle {
diff --git a/components/util/cursor.rs b/components/util/cursor.rs
index 622845deaa7..8e4ca9e3c1c 100644
--- a/components/util/cursor.rs
+++ b/components/util/cursor.rs
@@ -9,7 +9,7 @@ use std::ascii::AsciiExt;
 
 macro_rules! define_cursor {
     ($( $css: expr => $variant: ident = $value: expr, )+) => {
-        #[derive(Clone, Copy, PartialEq, Eq, Debug)]
+        #[derive(Clone, Copy, PartialEq, Eq, Debug, Deserialize, Serialize)]
         #[repr(u8)]
         pub enum Cursor {
             $( $variant = $value ),+
diff --git a/components/util/linked_list.rs b/components/util/linked_list.rs
index 5114f02c0e4..bf20f434d54 100644
--- a/components/util/linked_list.rs
+++ b/components/util/linked_list.rs
@@ -4,8 +4,81 @@
 
 //! Utility functions for doubly-linked lists.
 
+use mem::HeapSizeOf;
+
+use serde::de::{Error, SeqVisitor, Visitor};
+use serde::ser::impls::SeqIteratorVisitor;
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
 use std::collections::LinkedList;
+use std::marker::PhantomData;
 use std::mem;
+use std::ops::{Deref, DerefMut};
+
+pub struct SerializableLinkedList<T>(LinkedList<T>);
+
+impl<T> SerializableLinkedList<T> {
+    pub fn new(linked_list: LinkedList<T>) -> SerializableLinkedList<T> {
+        SerializableLinkedList(linked_list)
+    }
+}
+
+impl<T> Deref for SerializableLinkedList<T> {
+    type Target = LinkedList<T>;
+
+    fn deref(&self) -> &LinkedList<T> {
+        &self.0
+    }
+}
+
+impl<T> DerefMut for SerializableLinkedList<T> {
+    fn deref_mut(&mut self) -> &mut LinkedList<T> {
+        &mut self.0
+    }
+}
+
+impl<T: HeapSizeOf> HeapSizeOf for SerializableLinkedList<T> {
+    fn heap_size_of_children(&self) -> usize {
+        self.0.heap_size_of_children()
+    }
+}
+
+impl<T> Serialize for SerializableLinkedList<T> where T: Serialize {
+    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error> where S: Serializer {
+        serializer.visit_seq(SeqIteratorVisitor::new(self.0.iter(), Some(self.0.len())))
+    }
+}
+
+impl<T> Deserialize for SerializableLinkedList<T> where T: Deserialize {
+    fn deserialize<D>(deserializer: &mut D) -> Result<SerializableLinkedList<T>, D::Error>
+                      where D: Deserializer {
+        struct SerializableLinkedListVisitor<T> {
+            marker: PhantomData<T>,
+        }
+
+        impl<T> Visitor for SerializableLinkedListVisitor<T> where T: Deserialize {
+            type Value = SerializableLinkedList<T>;
+
+            #[inline]
+            fn visit_seq<V>(&mut self, mut visitor: V)
+                            -> Result<SerializableLinkedList<T>, V::Error>
+                            where V: SeqVisitor {
+                let mut list = LinkedList::new();
+                for _ in 0..visitor.size_hint().0 {
+                    match try!(visitor.visit()) {
+                        Some(element) => list.push_back(element),
+                        None => return Err(Error::end_of_stream_error()),
+                    }
+                }
+                try!(visitor.end());
+                Ok(SerializableLinkedList(list))
+            }
+        }
+
+        deserializer.visit_seq(SerializableLinkedListVisitor {
+            marker: PhantomData,
+        })
+    }
+}
 
 /// Splits the head off a list in O(1) time, and returns the head.
 pub fn split_off_head<T>(list: &mut LinkedList<T>) -> LinkedList<T> {
diff --git a/components/util/opts.rs b/components/util/opts.rs
index 9ba7f86a6d2..550dd2a408e 100644
--- a/components/util/opts.rs
+++ b/components/util/opts.rs
@@ -140,6 +140,9 @@ pub struct Opts {
     /// Dumps the display list after a layout.
     pub dump_display_list: bool,
 
+    /// Dumps the display list in JSON form after a layout.
+    pub dump_display_list_json: bool,
+
     /// Dumps the display list after optimization (post layout, at painting time).
     pub dump_display_list_optimized: bool,
 
@@ -178,6 +181,7 @@ pub fn print_debug_usage(app: &str) -> ! {
     print_option("disable-text-aa", "Disable antialiasing of rendered text.");
     print_option("dump-flow-tree", "Print the flow tree after each layout.");
     print_option("dump-display-list", "Print the display list after each layout.");
+    print_option("dump-display-list-json", "Print the display list in JSON form.");
     print_option("dump-display-list-optimized", "Print optimized display list (at paint time).");
     print_option("relayout-event", "Print notifications when there is a relayout.");
     print_option("profile-tasks", "Instrument each task, writing the output to a file.");
@@ -248,6 +252,7 @@ pub fn default_opts() -> Opts {
         user_agent: None,
         dump_flow_tree: false,
         dump_display_list: false,
+        dump_display_list_json: false,
         dump_display_list_optimized: false,
         relayout_event: false,
         validate_display_list_geometry: false,
@@ -424,6 +429,7 @@ pub fn from_cmdline_args(args: &[String]) {
         enable_canvas_antialiasing: !debug_options.contains(&"disable-canvas-aa"),
         dump_flow_tree: debug_options.contains(&"dump-flow-tree"),
         dump_display_list: debug_options.contains(&"dump-display-list"),
+        dump_display_list_json: debug_options.contains(&"dump-display-list-json"),
         dump_display_list_optimized: debug_options.contains(&"dump-display-list-optimized"),
         relayout_event: debug_options.contains(&"relayout-event"),
         validate_display_list_geometry: debug_options.contains(&"validate-display-list-geometry"),
diff --git a/components/util/range.rs b/components/util/range.rs
index 2c66c24dcd1..d0143a30340 100644
--- a/components/util/range.rs
+++ b/components/util/range.rs
@@ -124,7 +124,7 @@ macro_rules! int_range_index {
 }
 
 /// A range of indices
-#[derive(Clone, RustcEncodable, Copy)]
+#[derive(Clone, RustcEncodable, Copy, Deserialize, Serialize)]
 pub struct Range<I> {
     begin: I,
     length: I,
diff --git a/ports/cef/Cargo.lock b/ports/cef/Cargo.lock
index 3f69d1e34c8..04b6aa675b3 100644
--- a/ports/cef/Cargo.lock
+++ b/ports/cef/Cargo.lock
@@ -444,9 +444,11 @@ dependencies = [
  "rand 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "script_traits 0.0.1",
+ "serde 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_macros 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "skia 0.0.20130412 (git+https://github.com/servo/skia)",
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "time 0.1.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 0.2.35 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -571,7 +573,7 @@ dependencies = [
  "mac 0.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "phf 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "phf_macros 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_plugin 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "tendril 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "time 0.1.26 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -712,8 +714,10 @@ dependencies = [
  "script 0.0.1",
  "script_traits 0.0.1",
  "selectors 0.1.0 (git+https://github.com/servo/rust-selectors)",
+ "serde 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_macros 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_plugin 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "url 0.2.35 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -863,6 +867,8 @@ dependencies = [
  "log 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "msg 0.0.1",
  "png 0.1.0 (git+https://github.com/servo/rust-png)",
+ "serde 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_macros 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "stb_image 0.1.0 (git+https://github.com/servo/rust-stb-image)",
  "url 0.2.35 (registry+https://github.com/rust-lang/crates.io-index)",
  "util 0.0.1",
@@ -1108,6 +1114,7 @@ dependencies = [
  "hyper 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "ipc-channel 0.1.0 (git+https://github.com/pcwalton/ipc-channel)",
  "js 0.1.0 (git+https://github.com/servo/rust-mozjs)",
+ "layout_traits 0.0.1",
  "libc 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "msg 0.0.1",
@@ -1121,7 +1128,7 @@ dependencies = [
  "script_traits 0.0.1",
  "selectors 0.1.0 (git+https://github.com/servo/rust-selectors)",
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_plugin 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "tendril 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1139,9 +1146,12 @@ version = "0.0.1"
 dependencies = [
  "devtools_traits 0.0.1",
  "euclid 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ipc-channel 0.1.0 (git+https://github.com/pcwalton/ipc-channel)",
  "libc 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "msg 0.0.1",
  "net_traits 0.0.1",
+ "serde 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_macros 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 0.2.35 (registry+https://github.com/rust-lang/crates.io-index)",
  "util 0.0.1",
 ]
@@ -1157,7 +1167,7 @@ dependencies = [
  "matches 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "quicksort 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_plugin 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1263,13 +1273,14 @@ dependencies = [
 
 [[package]]
 name = "string_cache"
-version = "0.1.5"
+version = "0.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "lazy_static 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "phf 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "phf_macros 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_plugin 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_shared 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -1305,8 +1316,10 @@ dependencies = [
  "plugins 0.0.1",
  "rustc-serialize 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "selectors 0.1.0 (git+https://github.com/servo/rust-selectors)",
+ "serde 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_macros 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_plugin 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 0.2.35 (registry+https://github.com/rust-lang/crates.io-index)",
  "util 0.0.1",
diff --git a/ports/gonk/Cargo.lock b/ports/gonk/Cargo.lock
index 6f4357d4003..74e138ae5f6 100644
--- a/ports/gonk/Cargo.lock
+++ b/ports/gonk/Cargo.lock
@@ -423,9 +423,11 @@ dependencies = [
  "rand 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "script_traits 0.0.1",
+ "serde 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_macros 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "skia 0.0.20130412 (git+https://github.com/servo/skia)",
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "time 0.1.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 0.2.35 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -505,7 +507,7 @@ dependencies = [
  "mac 0.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "phf 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "phf_macros 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_plugin 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "tendril 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "time 0.1.26 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -646,8 +648,10 @@ dependencies = [
  "script 0.0.1",
  "script_traits 0.0.1",
  "selectors 0.1.0 (git+https://github.com/servo/rust-selectors)",
+ "serde 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_macros 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_plugin 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "url 0.2.35 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -789,6 +793,8 @@ dependencies = [
  "log 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "msg 0.0.1",
  "png 0.1.0 (git+https://github.com/servo/rust-png)",
+ "serde 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_macros 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "stb_image 0.1.0 (git+https://github.com/servo/rust-stb-image)",
  "url 0.2.35 (registry+https://github.com/rust-lang/crates.io-index)",
  "util 0.0.1",
@@ -1016,6 +1022,7 @@ dependencies = [
  "hyper 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "ipc-channel 0.1.0 (git+https://github.com/pcwalton/ipc-channel)",
  "js 0.1.0 (git+https://github.com/servo/rust-mozjs)",
+ "layout_traits 0.0.1",
  "libc 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "msg 0.0.1",
@@ -1029,7 +1036,7 @@ dependencies = [
  "script_traits 0.0.1",
  "selectors 0.1.0 (git+https://github.com/servo/rust-selectors)",
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_plugin 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "tendril 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1047,9 +1054,12 @@ version = "0.0.1"
 dependencies = [
  "devtools_traits 0.0.1",
  "euclid 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ipc-channel 0.1.0 (git+https://github.com/pcwalton/ipc-channel)",
  "libc 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "msg 0.0.1",
  "net_traits 0.0.1",
+ "serde 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_macros 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 0.2.35 (registry+https://github.com/rust-lang/crates.io-index)",
  "util 0.0.1",
 ]
@@ -1065,7 +1075,7 @@ dependencies = [
  "matches 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "quicksort 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_plugin 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1161,13 +1171,14 @@ dependencies = [
 
 [[package]]
 name = "string_cache"
-version = "0.1.5"
+version = "0.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "lazy_static 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "phf 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "phf_macros 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_plugin 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_shared 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -1203,8 +1214,10 @@ dependencies = [
  "plugins 0.0.1",
  "rustc-serialize 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "selectors 0.1.0 (git+https://github.com/servo/rust-selectors)",
+ "serde 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_macros 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "string_cache_plugin 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 0.2.35 (registry+https://github.com/rust-lang/crates.io-index)",
  "util 0.0.1",